I just got to Wisp with Assassin, Dante, Murloc,and the Worker. I thought that what you need to do is surround the Wisp's spawn with Riflemen and chain stun it to death, but the Riflemen didn't have a chance to start attacking, they just died.

We got it to about 75% by just straight up fighting it but then it had a fear effect and killed us. So if worker doesn't work, what's the way to kill the wisp? Version was 1.22d if there have been changes in the past that effected the worker strat.

Reduce its armor. It only has 400. A well-stacked Assassin can easily outleech his DPS or just outright Execute him to instant death in one shot if its armor is below 0. Assassin + Keeper of the Sky (with Decapitator and Darkness Broach) can kill him in duo without much trouble.